Method for producing bulked, highly stretchable textured cotton yarns



United States Patent 3,127,732 METHOD FUR PRODUCING BULKED, HIGHLYSTRETCLE TEXTURED CGT'ION YARNS John J. Brown, New Orleans, and GeorgeF. Ruppenicker, Jr., Metairie, La, assignors to the United States ofAmerica as represented by the Secretary of Agriculture No Drawing. FiledSept. 18, 1961, Ser. No. 139,005 8 Claims. (Cl. 57-164) (Granted underTitle35, U.S. Code (1952), sec. 266) A nonexclusive, irrevocable,royalty-free license in the invention herein described, throughout theworld for all purposes of the United States Government, with the powerto grant sublicenses for such purposes, is herebygranted to theGovernment of the United States of America.

This invention relates to cotton yarns that exhibit high stretch andsubsequent recovery from stretch characteristics together with inherentbulk. The production .of these cotton yarns is likewise the subject ofthis invention. The yarns that are the subject of this invention haveparticular utility in the manufacture of upholstery, rugs, and certainitems of Wearing apparel where yarns with considerable bulk and goodstretch and stretch recovery are required.

In general, the cotton yarns of this invention are pro-,

duced by resin treating plies of a plurality of single yarns having thesame directional twist, the yarns having been twisted during plying inthe same direction as theseveral singles from which it was made, with acrosslinking type resin and heat curing the resin. The twist in theresultant plied yarn is subsequently set in position by heat curing theresin and the yarns carrying the cured resin treatment are thenbacktwisted. The backtwisted yarn, when relaxed tends to return to theposition inwhich it was set when the resin was cured. The component yarnstrands separate and the relaxed, backtwisted resin treated yarn takeson the appearance of multiple, helical coiled springs, each yarn strandforming coils. in the direction of the backtwist.

When tensioned and fully extended, the yarns that are the subject ofthis invention resemble ordinary plied yarns.

It isknown to treat yarns made from continuous synthetic. filaments byheating, twisting. crimping, .and various combinations of thesetreatments and thereby to produce stretch or the so-called elasticyarns, but the production of yarns that possess these characteristicsfrom relatively short discontinuous fibers such as those of cotton has,until now, not been accomplished.

We have found various modifications of our basic procedure that aredesirable for producing particular products.

We can, for example, resin treat cotton sliver, dry with out heatcuring, draw the treated sliver into roving, spin the roving intosingles yarn, and ply the yarns in the same direction as the twist inthe single components. The resultant plied yarn after receiving therequired twist is heat cured. The heat curing of the resin serves to setthe yarn in its twisted position. The yarn is then washed, dried, andbacktwisted. Roving may be handled in similar fashion.

Another method is to treat single yarns with resin during a wet twistingoperation whereby the yarns are plied in the same direction as the twistin the single components. The yarns are subsequently made into skeins toprevent resin migration during drying in a conventional oven. Theresin-treated yarns are then cured, washed, dried, and backtwisted.

Dielectric heat can be used to dry and cure the highly twisted pliedyarns in package form, since this method of heating provides a uniformheat throughout the package and minimizes resin migration. The singleyarns are 3,127,?32 Patented Apr. 7, 1964 have concluded that dimethylolethyleneurea and urea formaldehyde are two of the best; however, we havefound that any resin treatment wherein crosslinking is involved (i.e.,the resin treating reagent is at least difunctional) will yield goodresults with our process.

The bulk and the stretch of the cotton yarnsthat are the subject of thisinvention are controlled by varying the amount of twist inthe componentyarns, the amount of ply twist prior to heat curing, and the amountofbacktwist after the yarn has been set by heat curing of the resin. Fora given yarn size, the size of the helical coils in the relaxed yarn,alluded to earlier in this disclosure, is governed to some extentby theamount of twist in the original single yarns that go into the plies. Asthe twist of the singles is decreased, the coils become larger and theyarn can be straightened by less tension. The amount of ply twistandbacktwist given to the yarn control the number of coils, the numberof coils per inch increasing with increasing twist.

t The following are detailed descriptions of methods for producing theproducts of our invention. As will be apparent to those skilled in theart, either a Z twist or an Stwist can be used in the single yarns atthe start. If S twist singles are used, these are plied with an S twist.on top of the S twist singles and then backtwisted to a Z twist afterthe resin treatment.

Example 1 Single yarn-24/ 1, 19.6 t.p.i. 2 was plied to produce- 24/2,20.8 t.p.i. Z Z twist on top of Z twist). The 'plied yarn was wound onperforated fiber tubes (approximately by weight of an acid salt catalystand .Ol%fby weight of a Wetting agent. After treatment the yarns werecentrifuged to a 65-70% by weight pick-up of the treating solution. Thispick-up with the strength resin solution indicated accomplishes about a4% by weight resin addon to the yarn (yarn contained approximately 1% byweight of nitrogen).

The resin-treated yarn was dried and heat cured for five minutes bymeans of dielectric heating using an applied voltage of ten kilovolts, afrequency of forty megacycles and a spacing between plates of seveninches. After curing, the yarns were washed free of unreacted reagentand catalyst, dried, and backtwisted 34.6 t.p.i.

Example 2 Single yarn-24/ 1, 22 t.p.i. 2 was plied to produce 24/ 3,17.0 t.p.i. Z (Z twist on top of Z twist). The yarn was treated with a10% by weight aqueous solution of dirnethylol ethyleneurea whichsolution contained in addition 1.5 by weight of an acid salt catalystand .Ol% by weight of a wetting agent, during the plying operation. A65-70% by weight wet pick-up was obtained by adjusting the twisterspeed. The yarns were then made into skeins, dried in an oven at C. forten minutes, cured in an oven at C. for six minutes, washed free ofunreacted reagent and catalyst and dried. The result was a 4% by weightresin add-on. The dried yarn was then backtwisted 29.8 t.p.i.

Example 3 from 7080% was obtained, resulting in a resin add-on of about7.5%. After treatment the skeins of yarn were dried in an oven at 80 C.for ten minutes, cured in an oven at 160 C. for six minutes, washed freeof unreacted reagent and catalyst and dried. The dried yarn was thenbacktwisted 29.8 t.p.i.

Example 4 Sliver was treated on a padder with a by weight aqueoussolution of dimethylol ethyleneurea which solution contained in addition1.5% by weight of an acid catalyst and .01% by weight of a wettingagent. The pressure between the rolls of the padder was adjusted toobtain a 65-70% by weight wet pick-up. After treatment the sliver wasdried in an oven. The sliver containing the dried but uncured resin wasthen processed into single yarn-24/ 1, 19.6 t.p.i. Z and plied toproduce 24/2, 20.8 t.p.i. Z (Z twist on top of Z twist). The yarns werethen cured in an oven at 160 C. for six minutes, washed free ofunreacted reagent and catalyst, dried and backtwisted 34.6 t.p.i.

The yarns described in Examples 1-4 above were capable of completerecovery after being stretched to approximately 400% of their relaxedlength. The yarns may appear to lose their stretch properties when keptin an ex- Y tended position, such as being stored on bobbins, for arality of single yarns having the same directional twist,

the plied yarn being twisted during plying in the same direction as theseveral singles from which it is made; treating the plied yarn with aheat curing resin of the crosslinking type; curing the plied resintreated yarn to set the initial yarn twist; and backtwisting the resintreated and cured yarn.

2. The process of claim 1 wherein additional twist is applied to theyarn prior to the resin treatment.

3. The process of claim 1 wherein the plied yarn being twisted duringplying is simultaneously subjected to the resin treatment.

4. The process of claim 1 wherein the resin employed is selected fromthe group of crosslinking resins consisting of dirnethylol ethyleneureaand tris(1-aziridiny1)phosphine oxide.

5. The process of claim 4 wherein the resin is dimethylol ethyleneureain an amount suificient to provide a resin add-on of about 4% by weightbased on the weight of the untreated, plied yarn.

6. The process of claim 4 wherein the resin employed istris(1-aziridinyl)phosphine oxide in an amount sufficient to provide aresin add-on of about 7.5% by weight based on the weight of theuntreated plied yarn.

7. A process for producing stretchable cotton yarns comprising thefollowing operations to be carried out in sequence: resin treatingcotton sliver with a heat curable, crosslinking type textile treatingresin; drying the resin treated sliver; drawing and spinning theresin-treated sliver into yarn; plying single yarns of the samedirectional twist into plies of a plurality of single yarns, the pliedyarns having the same directional twist as the single yarns from whichthey are made; heat treating the plied yarns to cure the resin and setthe initially installed and inherent twist in the plied yarns; andbacktwisting the resin treated and heat cured yarns.

8. A process for producing stretchable cotton yarns comprising thefollowing operations to be carried out in se-- quence: resin treatingcotton roving with a heat curable, crosslinking type textile treatingresin; drying the resin treated roving; spinning the resin-treatedroving into yarn; plying single yarns of the same directional twist intoplies of a plurality of single yarns, the plied yarns having the samedirectional twist as the single yarns from which they are made; heattreating the plied yarns to cure the resin and set the initiallyinstalled and inherent twist in the plied yarns; and backtwisting theresin treated and heat cured yarns.

References Cited in the file of this patent UNITED STATES PATENTS2,463,618 Heberlein et a1. Mar. 8, 1949 2,957,746 Buck et a1. Oct. 25,1960 3,039,167 Lund June 19, 1962 3,069,838 Wallays Dec. 25, 1962

1. A PROCESS FOR PRODUCING STRETCHABLE COTTON YARNS COMPRISING THEFOLLOWING SEQUENTIAL OPERATIONS: PLYING A PLURALITY OF SINGLE YARNSHAVING THE SAME DIRECTIONAL TWIST, THE PLIED YARN BEING TWISTED DURINGPLYING IN THE SAME DIRECTION AS THE SEVERAL SINGLES FROM WHICH IT ISMADE; TREATING THE PLIED YARN WITH A HEAT CURING RESIN OF THECROSSLINKING TYPE; CURING THE PLIED RESIN TREATED YARN TO SET THEINITIAL YARN TWIST; AND BACKTWISTING THE RESIN TREATED AND CURED YARN.